Recent efforts to reduce greenhouse gas emissions have revealed different policy priorities; the United States and China have emphasized subsidy-based approaches, and the European Union has emphasized carbon pricing. These divergent policy choices-some lowering energy costs, others raising them-raise concerns about industry competitiveness and have implications for upstream and downstream firms in supply chains. This paper identifies the trade tensions resulting from varying climate policy approaches and describes policy efforts to address them. It then describes the role of a rules-based trading system in tackling the challenges that these distinct policy approaches create, examining WTO rules on subsidies, border measures, and export restrictions. We suggest that the United States, the European Union, and China prioritize reforms to those rules as a path forward for cooperation on trade and climate. Such an approach would be an important starting point toward creating a functioning multilateral system.